Guinea Pig

The guinea pig (Cavia porcellus) is a sociable rodent and a popular choice of household pet. Adults typically weigh between 700 g and 1,200 g and measure between 20 and 25 cm in length. Most have fur, though coat length and texture vary widely across breeds - from the short, smooth English shorthair to long-haired varieties such as the Peruvian and the Silkie, and even a mostly furless type called the skinny pig.

Guinea pigs are popular pets in the UK, valued for their docile nature and their friendly responsiveness to handling. They are also kept by breeders for competitive showing, and organisations dedicated to this exist worldwide - including the British Cavy Council, which governs cavy clubs across the UK.

Guinea pigs were first domesticated as early as 5000 BC by tribes in the Andean region of South America - in what is now Colombia, Ecuador, Peru, and Bolivia - originally as a food source. Their closest wild relatives include species such as Cavia tschudii, which studies suggest is the most likely ancestor of the domestic guinea pig. Wild cavies are found on grassy plains in South America and live in small social groups.

In the early 1500s, Spanish, Dutch, and English traders brought guinea pigs to Europe, where they quickly became popular exotic pets among the upper classes and royalty, including Queen Elizabeth I. The earliest known European illustration of a domestic guinea pig is a painting dated to 1580, held at the National Portrait Gallery in London. The oldest recorded guinea pig remains in England - a partial skeleton - were found at Hill Hall, an Elizabethan manor house in Essex, and date to around 1575.

Despite their name, guinea pigs are not from Guinea, nor are they closely related to pigs. The exact origin of the name is unclear. One suggestion is that they were brought to Europe via Guinea, leading people to assume that was their homeland. Another is that "guinea" was simply a common English term for any far-off, unknown place - a nod to their exotic origins. It is not clear how they came to be called "pig", though they are built somewhat like pigs, make some pig-like sounds, and spend a large amount of time eating.

Through selective breeding over centuries, many breeds with varying coat colours and textures have been developed. The British Cavy Council governs cavy clubs in the UK today.

Guinea pigs are social animals that live naturally in small groups. They are generally timid and startle easily - when they sense danger, they either freeze in place or dart rapidly for cover. In larger groups, startled guinea pigs may stampede in different directions to confuse predators. Despite this skittishness, guinea pigs that are handled correctly from an early age become comfortable being picked up and rarely bite or scratch.

They are curious animals and will explore freely when in familiar, safe surroundings. Guinea pigs that have bonded with their owner will often "wheek" - a loud whistle - when that person approaches, and they quickly learn to associate sounds like rustling bags or a fridge opening with food. When happily excited, they sometimes perform little hops into the air, a movement known as "popcorning".

Guinea pigs communicate mainly through vocalisation. Common sounds include the wheek (excitement or calling out), a purring or bubbling sound (contentment), rumbling (dominance or courtship), teeth chattering (warning), and squealing (pain or fear). They also take part in social grooming and regularly groom themselves.

Unlike their wild relatives, guinea pigs do not follow a regular day-night pattern. Their activity is scattered throughout the day and night, with short periods of sleep in between, and they tend to avoid only very intense light.

Pet guinea pigs live an average of four to five years, though some reach eight years. The record, listed by Guinness World Records, is 14 years, 10 months, and 2 weeks.

Common health problems include respiratory tract infections, diarrhoea, scurvy (caused by vitamin C deficiency, since guinea pigs - like humans - cannot produce their own), abscesses, and infestations by lice, mites, or fungus. Mange mites can cause hair loss, excessive scratching, and in some cases seizures. Foreign bodies such as tiny pieces of hay can become lodged in the eyes, causing blinking, tearing, and sometimes corneal ulcers.

Guinea pigs are sensitive to temperature extremes. Their normal body temperature is 38-40°C, and they cope better with cold than heat - temperatures consistently above 32°C have been linked to heatstroke and death. They are also sensitive to most antibiotics, including penicillin, which can disrupt their gut flora and cause serious illness.

Some genetic conditions have been recorded. In Abyssinian guinea pigs, the roan coat colour is associated with congenital eye disorders and digestive problems. Other reported genetic conditions include deafness paired with a tendency to run in circles, and various palsy and tremor conditions. Pregnancy toxaemia is a known risk in breeding females, and older guinea pigs of both sexes can develop faecal impaction. Because guinea pigs instinctively hide signs of illness, health problems may not become obvious until they are already advanced.

This is general awareness only, not veterinary advice. Always consult a vet about your pet's health.

Are guinea pigs actually related to pigs?

No - despite the name, guinea pigs are rodents, not pigs. It is not clear how they got the "pig" part of their name, though they are built somewhat like pigs, with large heads and stout necks, some of their sounds resemble those made by pigs, and they spend a lot of time eating.

How long do guinea pigs live?

Pet guinea pigs live four to five years on average, though some reach eight years. The world record holder lived for 14 years, 10 months, and 2 weeks, according to Guinness World Records.

Do guinea pigs make a lot of noise?

Guinea pigs are quite vocal. They wheek (a loud whistle), purr, rumble, chatter their teeth, squeal, and occasionally make a chirping sound similar to birdsong. They often wheek when they hear their owner approaching or when they hear food being prepared.

Can I keep a guinea pig with a rabbit?

Opinion is divided on this. Rabbits have different nutritional needs and can carry diseases - including respiratory infections from Bordetella and Pasteurella - to which guinea pigs are susceptible. Some published sources say the two species complement each other well, but they will not thrive if fed the same food when housed together.

Can guinea pigs make you ill or cause allergies?

Allergic reactions to guinea pigs have been reported, including runny nose, eye irritation, and asthma. Two specific allergens - Cav p I and Cav p II - have been identified in guinea pig urine, saliva, and dander. People allergic to guinea pigs are often also allergic to hamsters and gerbils.

Do guinea pigs need company?

Yes - guinea pigs are social animals and thrive in groups of two or more. Research shows that a boar's stress response in an unfamiliar environment is significantly reduced when a bonded female is present. In Switzerland and Sweden, keeping a guinea pig without a companion is actually against the law.

Guinea pig babies - called pups - are born remarkably well-developed. Unlike most rodent newborns, they arrive with fur, teeth, claws, and partial eyesight, and are able to eat solid food almost immediately.

The phrase "guinea pig", meaning a human test subject, came directly from these animals. They were used so frequently in medical research during the 19th and 20th centuries that their name became a common expression in everyday English.

Guinea pigs can accurately remember a route to food for months after first learning it. Their favourite problem-solving approach is simply to keep moving.

The earliest known painting of a domestic guinea pig in Europe - dated to 1580 - hangs in the National Portrait Gallery in London. It shows a girl in Elizabethan dress holding a tortoiseshell guinea pig, flanked by her brothers.